The invention relates to an aircraft comprising an onboard weather radar antenna fitted with inclined panels.
Onboard weather radar systems are usually installed in the nose cone of aircraft. They detect weather conditions on the aircraft trajectory.
FIG. 1 shows the known architecture of an onboard weather radar antenna. The antenna comprises an approximately circular panel P fixed on a mechanical support 1. The panel P is connected to a source of electromagnetic waves (not shown in the figure). The circle that is defined by the panel P is centered in an orthogonal coordinate system (Y, Z), the Y and Z axes are coincident with a horizontal and a vertical respectively when the aircraft is on the ground. The panel P is capable of moving around the Y and Z axes in the (Y, Z) coordinate system, to scan through the space in front of the aircraft. The antenna is installed behind a radome (not shown in the figure), that protects it from atmospheric disturbances and relative wind. The radome is composed of a material transparent to wavelengths transmitted and received by the antenna.
The ARINC (Aeronautical Radio INCorporated) standard that fixes communication standards inside aircraft and between aircraft and the ground also fixes geometric constraints for installation of the antenna behind the radome. These geometric constraints are shown in FIG. 1 by the spherical volume V. The volume V defines the space dedicated to the weather radar antenna.
Modifications in the orientation of the panel P in the volume V defined by the ARINC standard are shown in FIGS. 2A to 2C. The weather radar antenna is positioned in a housing delimited by a radome R and a sealed wall K fixed to the aircraft fuselage F. The panel P of the antenna is fixed on the mechanical support 1. FIG. 2A shows the case in which the antenna panel P is located in a plane perpendicular to the longitudinal axis X1X2 of the aircraft. In FIGS. 1 to 2C, the Z axis represents the vertical axis or the height, considered when the aircraft is on the ground. FIG. 2B shows the case in which the antenna panel is at its stop for an azimuth rotation, in other words a rotation about the Z axis. FIG. 2C shows the case in which the antenna panel is at its stop for a rotation in elevation, in other words about the Y axis perpendicular to the Z and X1X2 axes. In a manner well known to aircraft manufacturers and as shown in the figures described above, modifications to the orientation of the panel P in azimuth and in elevation require a large antenna housing, thereby significantly increasing the length of aircraft (along the X1X2 axis).
The invention is aimed at reducing the dimensions of the housing necessary to change the orientation of an onboard weather radar antenna in an aircraft.